Dramatic progress has been made in the fields of cell and developmental biology in recent years, largely due to the application of new technical approaches to classical problems. This has led to the need for advanced courses to train new investigators to study those animal models, such as the frog, Xenopus, that have been important in making new discoveries. Funds are being sought to continue the Cold Spring Harbor Laboratory course on Cell and Developmental Biology of Xenopus which has been taught for twenty one years as part of an integrated set of courses in a number of areas of modern biology. This course provides extensive laboratory exposure to the biology and manipulation of embryos from the frogs Xenopus laevis and Xenopus tropicalis. This course prepares students for independent research in the cell, genetic, and molecular analysis of vertebrate development. It introduces the unique attributes of Xenopus which allow the functional analysis of developmentally important genes, whilst at the same time introducing the major technologies of modern molecular and cellular developmental biology, in a system that allows direct manipulation of embryos and visualization of developmental processes. At the end of the course, students are ready for cutting edge research. The Cell and Developmental Biology of Xenopus course is designed to train students how to take advantage of these unique qualities. It is often difficult for investigators to initiate studies of Xenopus development on thir own because the techniques for raising embryos or manipulating them are unfamiliar or because their background knowledge of developmental biology is inadequate. This course is designed to provide students with a concentrated and repeated exposure to the most important research techniques, and the researchers doing them, so that they initiate their own independent research projects after returning to their home institutions. The course provides an intensive exposure, over an eleven-day period, to the biology and manipulation of Xenopus embryos. The course also provides a resource network that the students can easily access after they have returned to their home laboratories. Through these routes, the course trains investigators at the advanced graduate, postdoctoral and faculty levels to use Xenopus in their research It is anticipated that the basic organization of the course and some of the basic course material will remain unchanged during the proposed period of support. However, new and fast-developing topics will be discussed and integrated into the course as the field progresses.